Heat assisted magnetic recording (HAMR) generally refers to the concept of locally heating a recording medium with a laser to reduce the coercivity. This allows the applied magnetic writing fields to more easily direct the magnetization during the temporary magnetic softening caused by the heat source. HAMR allows for the use of small grain media, with a larger magnetic anisotropy at room temperature to assure sufficient thermal stability, which is desirable for recording at increased areal densities. HAMR can be applied to any type of magnetic storage media including tilted media, longitudinal media, perpendicular media, and patterned media. By heating the media, the Ku or coercivity is reduced such that the magnetic write field is sufficient to write to the media. Once the media cools to ambient temperature, the coercivity has a sufficiently high value to assure thermal stability of the recorded information.
Close proximity of the heat source and magnetic write pole is essential for successful HAMR. A number of techniques have been proposed to deliver electromagnetic energy to the NFT. In some, the source is remote to the slider containing the recording head and directs energy to the NFT via waveguides mounted on the slider. Another uses optical fibers to deliver energy to the slider from remotely mounted lasers. Optical fibers are stiff and affect the slideability of the slider in a disc drive system. Micro electromechanical (MEM) mirrors have also been suggested for energy delivery. Recent solutions have suggested mounting the laser directly on the slider thereby eliminating peripheral, optical, and other system components. Mounting the laser on the slider simplifies the energy delivery system for HAMR but the process of individually aligning each laser results in high production costs and low alignment accuracy. There is a need for a compact, modular HAMR recording device that can provide localized heating without costly components and alignments.